Power over Ethernet

Hi trying to setup and play with Poe. I have plugged some splitters into a POE switch and also my Ubiquity 120v injector both don’t give any power over the out puts or any lights. If I look at the pigtail the wires that are for PoE seem to be missing.

Are you using passive PoE splitters with an active PoE switch? What do you mean you plugged the splitters and injector into a switch? Usually the PoE switch supplies the power.

The splitter is also being hooked up backwards.

That is the Data out no power side.

the power goes out the usb

the power and Data from the switch comes in the female side of the splitter

The splitter says it is active. I will have to research what exactly what that means.

This is the switch but can find if it is active or passive.

I plugged the splitter into the cheap switch no so then I plugged it into a Ubiquity power injector and there was still no lights.

That makes sense. So the only power out is the usb pig tail. I don’t get any power out of that either.

Edit: I’m seeing something about needing 48v on the switch before the splitter will power up.

@PotatoFarmer cant recall seeing the voltage you were feeding yours but I think you talked of 24.

I can’t even test 48 as my power supply doesn’t go that high.

24V is for steering

All switches PoE tried so far use 48V input. Im sticking with the standard because it has many benefits including built in short protection.

Active means it requires a POE switch that supports 802.3at or af, which is 48v, and automatically detects which pins are used for power, and can even multiplex data and power down the same wires for gigabit speed.

I’m using several of those splitters to run various single-board computers off of my powered switch. The Switch has to support 48v 802.3af or 802.3at active POE. The little splitter plugs into the switch port with a patch cable, and then breaks out a 100 mbit ethernet pigtail (the reason there are only 4 wires in the ethernet plug), and then converts the 48v to 5V USB to run my SBC.

I also have another converter that adapts active 802.3af to passive 24V POE to run some ubiquiti antennas I have on my shop. Also nice because it eliminates the need for power injectors.

My POE switch can supply 150 watts total to various devices. Handy for running cameras as I only need to run one ethernet wire out to the location where the camera is mounted.

Sorry to hijack this thread but is there any easy implementation of POE injectors available? I am actually kind surprised there isn’t a whole lot more about it online. All I seem to be finding is just people pulling a few wires out of the cable and using those.

Passive POE implementations all seem to put +24V on the blue wires (4 and 5), and Gnd on Brown wires (7 and 8). So easiest is to just pull out the wires when making up the cable.

But here is a POE injector that’s DC only, suitable for use in a tractor cab: Tycon Systems 12VDC In, 24V Passive PoE Inserter | Tycon Distributor

These work well for passive PoE and are compatible with most commercial passive PoE power supplies & injectors.

axGear Passive Power Over Ethernet PoE Adapter Injector+ Splitter Kit 5v 12v 24v 48v

But you can’t mix active with passive and expect it to work.

When buying from AliExpress you pretty much need to reverse engineer the “Poe” switch to know what it’s actually doing because their support is so poor.

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Here’s a passive poe adapter for use with switches that support 802.3af/at. Expensive though. But convenient. https://www.amazon.ca/UBIQUITI-INS-3AF-Instant-802-3af-Converter/dp/B01N0W5UL1

I had the problem with interferences in tractors radio, therefore keep an eye on a proper shielded version!

Shielded ethernet cables have caused AOG issues before. The plugs at each end of the cable are electrically bound to each other through the shield. That’s not good when one side of the cable plugs into an autosteer box where the jack is at ground potential, and the other side of the cable plugs into a jack at the tablet that has a floating ground potential because of the tablet’s boost converter.

Rule of thumb in Industrial control wiring is “No shield in the field”, meaning only terminate the shield at the negative of the power supply only.

Not at both ends. You want the induced interference to bleed to ground, not create a ground loop.

Im interested in this interference, will have to plug into a nice quiet pickup truck and see what happens to its radio.

So far have not shielded anything, using standard af/at equipment. Circuit boards are covered by a thin plastic bag for an enclosure. Nothing is grounded in any special way. Other than the negative of the power supply goes directly to the battery.